Tail multi-parameter optimization of Ahmed model based on response surface method

To solve the problem of wind noise and structural resistance caused by vehicle external structural parameters, this paper carried out multi-objective optimization for the tail multi-parameters. Based on the selected four parameters of C-Pillar angle, trunk angle, rear box length and boat tail angle of Ahmed model, the central combination test design of response surface Box-Benhnken was carried out in the selected range. The sampled data sets were numerically simulated in star-ccm+, and the surface sound pressure level and drag coefficient of the model were obtained. The optimal Latin hypercube sampling data sets were used to verify the accuracy. Finally, the response surface model was established, and the optimal front window surface SPL was 65.11dB with an error of 1.36%, and the optimal drag coefficient was 0.1210 with an error of 1.68%, taking Curle SPL and drag coefficient as the optimization objective.